This report presents the work of two semesters in collaboration with Aalborg University hospital. It is centred around identification of requirements for arterial blood gas results through an IT application. The report includes two articles. The first focuses on working with such a complex domain within limited time scope. A complex domain introduces difficulties in the communication and it can be difficult to identify the requirements for both us and the physicians. The article introduces prototypes as boundary objects in order to facilitate communicate between the two stakeholders. We found boundary objects to externalise tacit knowledge and effective the communication. The use of multiple prototypes enables higher quality feedback and not using prototypes reduces the quality significant. The other articles focuses on the visualisation of rich data through a user interface. We developed an application that was evaluated with eight physicians at the hospital. The evaluation proved that sequential display of results on graphs helped identify trends and contextual information is necessary such as reference interval and treatment information. The adaptation of a new system was difficult which requires time to adjust as well as a customisable interface to fits the specific physician.